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Submitted to: Silverleaf Whitefly: 1997 Supplement to the Five Year National Research and
Publication Type: Abstract Only Publication Acceptance Date: 3/28/1997 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Since the early 1990's, the silverleaf whitefly has become an increasingly important insect pest of cotton in the Lower Rio Grande Valley (LRGV) of Texas. Several elite cotton germplasm lines developed and released by the USDA-ARS, Subtropical Agricultural Research Laboratory (SARL) in Weslaco, TX, possess traits that confer host plant resistance to the silverleaf whitefly. These traits include the glabrous and/or smooth-leaf characteristic and earliness in maturity. For two consecutive years, 1995-1996, the first bale of cotton harvested in the United States has been Texas 121, which is a glabrous, very early maturing variety. The Texas 121 variety is a mass selection of C21S781-2, a germplasm line developed by the USDA-ARS. The top yielding entry in the 1996 LRGV variety test, C118-2-93, had 0.54 leaf trichomes/cm2, compared to 0.79, 1.29, 4.66, 18.18, 19.93, and 87.48 leaf trichomes/cm2 for Deltapine 5409, Deltapine 51, Stoneville 495, Stoneville 132, Suregrow 125, and Stoneville 474, respectively. C118-2-93 and several other elite lines will be tested for resistance to the whitefly-transmitted crumple leaf virus in 1997. Two-year results from a three-year study showed that when comparing yields of the imidacloprid-treated plots to the whitefly-infested plots, average line yield was reduced 22% by whiteflies and 30% by reniform nematodes. Based on sequential harvest, the greatest yield losses in the whitefly plots were observed in the later harvests, indicating that whitefly damage increased as the season progressed and that managing for an early crop should have a significant impact on reducing damage. Micronaire value was reduced by 0.5 units in the whitefly-infested plots, indicating the potential effects of whiteflies on fiber maturity. |
